Electric discharge device



Nov. 4,1941. F, E. SU MERS 2,261,607

ELECTRIC DISCHARGE DEVICE Filed Oct, 1, 1934 Patented Nov. 4, 1941 ELECTRIC DISCHARGE DEVICE Frank E. Summers, near Memphis, Mo., assignor to Radio Corporation ofAmerica, New York, N. Y., a corporation of Delaware Application October 1, 1934, Serial No. 746,396

9 Claims.

My invention relates to improved electron'de- Vices of thethree, four or more electrode type, for use in transmission or reception, or both.

One object of my invention is to increase the internal capacity between the control grid electrode and the cathode electrode of four electrode screen grid tubes, and also between the outer grid and the anode electrode.

'Another object is to provide novel means to increase the efiiciency greatly of electron tubes for amplification and for generating oscillations.

Another object is to connect two grids direct together.

Another object is 'to provide means to increase the capacity of cathode electrodes, said means comprising a screen like capacitive element disposed co-axially around the cathode and con nected electrically inside the envelope of tube to said cathode electrode, whereby the capacity'of said cathode is greatly increased.

Another object is to provide means to both'increase the capacity 'and electron emissionof a cathode electrode, of filamentary structure.

Another object is to provide an electron device that ha's'certain electrodes composedof magnesium alloy, or magnesium wire mesh screen.

Another object is to provide a four electrodescreen grid tube with a capacitive grid like element disposed co-axially around the cathode electrode and connected inside the envelopeelec-- trically to said cathode, whereby the capacity of said filamentary cathode is greatly increased.

A still further object is to provide means to increase the efiiciency of both open air andevacutions, using cold cathodes in electron devices, or

discharge tubes.

A still further object is to use cold'cathodes having a large area subject to electron em-ission.-

With these and other objects of my invention in view which will appear as the disclosure of this specification proceeds with and in reference'tothe'accompanying drawing, my invention resides in the novel construction, proportion and relative arrangement of the elements specified and claimed.

- Referring to the accompanying drawing:

Figure 1 shows a diagrammatic disclosure of one modification of my invention.

Figure 2 shows another modification of my invention which discloses a screen, mesh like grid between the cathode and other electrodes of a four electrode screen grid tube.

Figure 3 shows my invention in combination with one preferred circuit whereby greatly increased efiiciency has been obtained, especially when the grid return of the input circuit is con-- nected to terminal 4A of grid 4.

Figure 4 shows diagrammatically a cross section of one preferable modification of my invention, disclosing the screen mesh'electrode 4 dis-I posed around the cathode 5, and grid electrode 1 disposed around screen mesh electrode capacitive element 4. Another grid electrode 3 is disposed around electrode 1, and the anode or plate electrode 2 is disposed around grid electrode 3.

Figure 5 shows my cold cathode tube and circuits therewith for the generation of oscillations.

Figure 6 shows a side View of the close spacing of the tube elements, for use in an envelope, or

tion disclosed in my application Serial No. 139,-- 479 filed Oct. 26, 1926, see Figure 5 in said application; and also is'the same 'invention'as disclosed in Figure 10 of my co-pending application Serial No. 568,066, filed Oct. 1, 1931.

Figure 10 discloses the outer grid 3 connected direct to the cathode electrode 5.

Figure 11 discloses two grid electrodes connected direct together, and a third grid electrode disposed between said grid electrodes thus connected. Also said grids thus connected are further connected direct to the cathode 5.

The figures are largely diagrammatic and show means whereby my invention has been carried into'effect.

This application is a continuation in part of my'co-pending applications, Serial No. 434,374

' filed March 8,1930; Serial No. 352,668 filed-April 5, 1929; Serial No; 684,545'filed January 5, 1924; Serial No. 409,847 filed'November'2'6, 1929; Se rial No; 87,599 filed February 11,1926; and Serial No. 706,980 filed January 17, 1934; and Serial No. 568,066 filed October '10, 1931; and Serial No. 685,033 filed August/14, 1933. This application also is a continuation in part through parent applications of certain common subject matter with my filed-applications Serial No. 431,-;

775'filed February 27, 1930; Serial No. 139,479

filed October 4, 1926; Serial No. 378,709, filed on or about May 3, 1920; and Serial No. 55,144 filed September 5, 1925. This application is also a continuation in part of my filed applications Serial No. 662,080 filed September 11, 1923; and Serial No. 139,479 filed October 4, 1926, through parent application 434,374 filed. March 8, 1930.

Referring to the drawing Figure 1 and Figure 2 disclose four electrode screen grid electron tubes with my invention added thereto. The envelope or receptacle I has four electrodes disposed therein, which are the cathode electrode 5, the inner grid electrode 1, the outer grid electrode 3 and the plate or anode 2, and the grid like element 4. As several years ago I discovered that means to increase the internal capacity of the cathode electrode and grid electrodes greatly increased the efiiciency of electron tubes for all purposes, I used capacitive elements in the form of plates and screen mesh grids and also spiral wire grids, to increase the internal capacity of cathode electrodes, which allows far more current to travel between the control electrode and the cathode electrode thus more greatly altering the electron emission of said cathode. I used grid like electrode 4 disposed co-axially around the cathode 5 and connected direct thereto electrically. In the modification I carried out in the open air using my invention,

I discovered that the ratio of amplification was greatly increased, also the tendency of the system to oscillate far more easier. In amplifying signals in open air devices the cathode and grid elements gave out the signals direct without using a. loudspeaker or telephone receiver. And when the open air electrodes were oscillating a singi g sound was sent out direct from said electrodes, this is because the modulated current going through the air between the electrodes acted as a telephone receiver or loudspeaker in causing the air to vibrate.

In some of my open air modificationsI used grids coated with iron-sulphide, lead-sulphide, oxide of calcium, and similar non-oxidizable substances, which were largely inert chemically to the atmosphere, and artificial gases. I also used grids coated with, and composed of magnesium but these after use tended to convert to magnesium compounds, these being some examples of the electron, or the impact electron, emitting elements I have used.

In some of my experiments I used the capacitive element 4 composed of electron emitting elements. I also used the grid electrode 3 composed of an electron emitting element. The grid electrode 1 I.prefer to use for many modifications of nickel or similar non-electron emitting substances at operating temperature.

In Figure 2 I show a single terminal cathode 5, heated by a double terminal heater 5A. I also show in Figure 4 a single terminal cathode 5. I used a grid 4 connected electrically direct to the single terminal cathode 5, in this manner a positive charge is not imparted to the grid 4.

In using electron emitting capacitive elements 4 connected conductively with the cathode '5 electron emission is increased. One example of elements I prefer to use is magnesium wire for capacitive element 4 and grid element 3'. The electron emission from the magnesium wire elements 4 and 3- increased photo-electrically, from the glowing filament 5 which causes the magnesium to throw off electrons. In some modifications I have found that I prefer to use grid electrode 3A composed partly of magnesium wire,-

because electron emission for many purposes is too great. The preferable amount of electron emission of grid-cathode 3 is determined by the amount of magnesium wire used. For the other wire of electrode 3 I prefer to use nickel.

One inherent function of electron emitting control grids, or grid, is to emit electrons direct when connected to the negative side of a source of electrical current as shown in the input circuit of Figure 3, which includes a serially connected source of electrical current with the negative side connected to the grid 3.

In Figure 3 I show means whereby the amplified energy of both the output circuit including grid 1, and the circuit including the anode 2, are added together by induction in a single circuit and used as the input circuit to a loudspeaker or to another similar or non-similar stage of amplification. The connections of the individual transformers l8 and 24 must be so poled that the induced energy is added together instead of being neutralized, the signals or pulsations in the inner grid circuit and in the plate circuit being out of phase.

It is obvious that connecting one side of the input circuit to the grid 3, and the other side to the grid 4 through terminal 4A, both grids operate simultaneously as control grids, or in other words when one grid of the input circuit is charged positively the other control grid is charged negatively at the same instant of time, and vice versa. This mode of operation applies in connecting the grid return of the input circuit to one of the terminals of the cathode 5, or to the terminal 4A. However in connecting to terminal 4A all the input current must go serially through the grid 4, thus affecting all the electron stream before it can reach the cathode 5. This action is true push-pull operation adapted to one tube, the result being that the added effect of both control grids greatly increase the undistorted-altered output of grid 1 circuit, or the plate 2 circuit, or of both output circuits. There is obtained far greater amplification without distortion, and at the same time clear bell like tone of the voice. The function of electrode 4 is to act in part as a cathode, a control-grid and a capacitive element.

I have used Figure 3 with the third grid connected direct to the cathode, the middle grid as the input grid, and the inner grid as the output electrode, and the inner grid and the anode connected to points on the B battery, both for audio and radio frequency amplification. The grid 3 or third grid screens the capacitive and inductive feed back around the electron flow in multistage applications. I

Figure 4 is a cross section of the preferred location of elements in an electron tube. This is largely self-explanatory. The cathode electrode 5 has disposed around same coaxially a second cathode electrode 4, which is connected electrically to element 5. thus in effect elements 5 and 4 constitute a single cathode electrode, which increases the internal capacity, the control effect, and also electron emission. Around cathodecapacitive element 4, is disposed co-axially the inner grid electrode 1, and around grid electrode 1 is disposed co-axially the outer grid electrode 3, and around the outer grid electrode 3 is disposed co-axially the plate electrode 2, and around the plate electrode 2 is disposed the grid like element 3, and said grid electrode 3 and grid like element 3A being connected together.

The first grid 4'is preferably composed of magnesium, coated with caesium, composed in part of iron-sulphide, lead-sulphide, oxide of calcium, mercury, or other suitable cold electron emitting elements. One object or function is to aid the cathode in increasing electron emission, largely by the photo-electric effect. Another function Where magnesium or aluminum is used as part of the grid 4 aids electro-chemically in maintaining a very high vacuum throughout the whole tub e life.

' In Figure 5 I disclose a radio tube I, having disposed therein a large fiat cathode 5 having an efiicient cold electron emitting substance, coated, plated or chemically formed thereon, such as magnesium, aluminum, alkali hydride, mercury, oxide of calcium, oxide of barium, oxide of strontium, iron sulphide, lead sulphide, silicon, or radio-active compounds or alloys of above elements and compounds. The tube I is a purely evacuated tube, or has disposed therein an inert atmosphere 2| such as helium, argon, krypton, iodine, bromine, chlorine, mercury, or air at low pressure, carbon dioxide, or a combination of these elements and compounds. The area of the cathode 5, grids 4 and I and anode 2 are preferably very large. The size of electrodes required vary with voltage used, conducting medium 2|, and spacing of electrodes. In one radio set I had good results in using cathode having an area of 3 by 6 inches, and other electrodes of similar size, in this modification I used a master oscillator, directing the oscillating current between all the elements of each of the tubes, for the purpose of decreasing the plate and grid voltage required and increasing the tonal qualities of speech and music.

In Figure 6 I show how the cathode, grid and anode elements are spaced.

In Figure '7 I show a heater 24 adjacent the anode. In this modification the anode electrode is preferably perforated. so as to allow the heat to more afiect all the electrodes. The anode 2 is preferably composed in part or wholly of some highly electro-negative substance or element such as nickel, copper, magnesium, lithium or alloys of these elements.

In Figure 10 I show a four electrode tube of my invention whereby the middle grid and the cathode 5 are in effect one electrode. This being one modification of my invention. All current must go through the spiral wound grid 1 before it reaches the cathode; this increases the efficiency of a radio tube for many uses.

In using my invention with present conventional radio tube circuits, and especially where no bias voltage is used in the input circuit, I prefer to use the grid electrode 1, which is also the input electrode in many conventional circuits, composed entirely of an electron emitting element, such as magnesium, or composed at least in part of magnesium. In order to make this tube universal I prefer to have the grid electrodes 1 and 3 composed entirely of magnesium, or composed in part of magnesium. I do not call the element 4 purely a grid electrode when connected electrically to the cathode electrode 5, but inherently a cathode control electrode in combination with cathode element 5, which also greatly increases the internal capacity between input electrodes, thereby greatly increasing the efiiciency of a four electrode tube as an oscillator and amplifier.

In Figure 11 there is shown a tube having two grids 4 and 3 connected directly together and a grid 1 disposed between said grids.

I am claiming basically in parent case No. 684,545 and No. 685,033, the connecting of one of the grid electrodes direct to the cathode electrode. Also broadly claiming cold electron'emitting electrodes generic to control and grid electrodes. Alsoclaiming certain cold cathode for use in an electron device. Also claiming helium gas to use in a radio tube. Also claiming means to reduce compounds. Also claimingmeans to form compounds.

I do not Want to be bound by the theories'or principles I have used herein, but after years of experimentation they are the best explanations I can give at present, it being obvious that I have provided systems that are far difierent from the old systems of Armstrong, Hull, De Forest, I-Ieising or Hartley. My systems obtain 'far greater efiiciency and are radically different from the old regenerative and oscillatory generating systems above mentioned. I

It is obvious that I have provided means to shunt the feed back energy from the anode around the electron flow, whether the first, second or third grid is connected directly to the cathode, This is an efficient invention when used with regeneration or radio-frequency amplification. Also in radio or audio-frequency amplification the efiiciency and tonal qualities are increased, by the increasing of the internal capacity between the input grid and the cathode electrode. Magnesium anodes comprise an element coated with magnesium, a magnesium alloy, or purely magnesium. This also applies to magnesium grids. I

' As shown in Figure 4, the grid electrodes are disposed closer to the anode than to the cathode electrode, this is for the purpose of decreasing the amperage required to operate the tube. The farther a grid electrode is away from the cathode the less amperage it will take, when grids are used with a positive potential this is very desirable in many circuits and systems.

It is to be understood that by modification of circuits shown in Figure 5 the system operates as a detector stage or as an amplifier stage. As a detector circuit the cold cathode 5 is composed of or in part of iron, silicon, iron sulphide, lead sulphide (galena ore), alloys or mixtures of same and similar materials. The anode being composed of copper, nickel or mercury amalgams, or alloys of same. Another modification is a cathode of silicon, or in part of silicon, and anode of mercury alloy, and a grid or control electrode. Another modification as a detector is a cathode electrode in part of silicon, anode and grid electrodes of palladium (or some other inert metal to iodine vapor) and iodine vapor disposed free in the envelope, also inert gas, or inert gas and iodine vapor free in the envelope.

In Figures 7, 9 and 10 the heater 24 is composed of a spiral winding. In Figure 10 the spiral continuous winding is disposed co-axially around the anode electrode.

My invention is only limited within the scope of the appended claims, it being obvious many modifications of my invention are possible without departing from the spirit of my invention.

Having described my invention what I claim as new and desire to secure by Letters Patent of the United States of America, is:

1. An electron discharge device comprising an envelope containing a cathode electrode, an anode electrode, a plurality of grid electrodes, and said anode electrode and said grid electrodes composed of metallic magnesium.

2. A five electrode tube comprisingan envelope containing a cathode electrode, an inner and outer grid electrode, a magnesium wire grid capacitive element disposed between said inner grid electrode and said cathode electrode, and said tube having an anode electrode.

3. A five electrode tube comprising an envelope containing a cathode electrode, an anode electrode, and inner and outer grid electrodes disposed between said cathode electrode and said anode electrode, a magnesium alloy grid element disposed between said cathode electrode and. said inner grid electrode, and said magnesium alloy grid element connected direct to said cathode electrode.

4. The combination in an electron discharge device of a ingle terminal electron emitting cathode, an anode, three grid electrodes disposed in succession between said cathode andv anode electrodes, and an outer grid wire element surrounding the anode and electrically connected to one of the said three grid electrodes, and the said cathode electrode electrically connected to one of the remaining said grid electrodes.

5. An electron discharge device comprising an envelope containing a cathode electrode capable of emitting light and an anode electrode, a'grid electrode coated with a photo-sensitive substance and disposed between said electrodes, said grid electrode connected direct to said cathode electrode whereby electro-emission of said cathode is increased photo-electrically.

6. A five electrode tube comprising an envelope containing a cathode electrode, an anode electrode, and inner and outer grid electrodes disposed between said cathode electrode and said anode electrode, a magnesium alloy grid element disposed between said cathode electrode and said inner grid electrode, and said alloy magnesium grid element connected direct to the negative side of said cathode electrode.

7. An electrical discharge device comprising a sealed envelope containing a single terminal electron emitting cathode, an anode, three grids disposed in succession between said cathode and said anode, each of the said grids disposed nearest to said anode and to said cathode being coated with an efficient cold electron emitting material and one of said grids thus coated being connected direct to said single terminal cathode,

and the remaining intermediate grid being composed of a non-electron emitting material.

8. An electrical discharge device comprising a sealed envelope containing a double terminal cathode, an anode, three grid electrodes disposed in succession between said cathode and said anode, both of said grid electrodes disposed nearest to said cathode and to said anode being coated with an efficient cold electron emitting material and one of said grid electrodes thus coated being connected direct tosaid double ter minal cathode, and the remaining intermediate grid electrode being composed wholly of a nonelectron emitting high fusible material.

9. A five electrode discharge tube comprising an envelope containing a cathode, an anode, three grid electrodes disposed in succession between said cathode and said anode, the grid disposed nearest to said cathode being a spiral wound wire grid having one end connected direct to the said cathode and the opposite end extending out through said envelope for an external electrical connection, and said spiral wound wire grid being coated with an eflicient cold electron emitting material.

FRANK E. SUMMERS. 

